Various techniques have been proposed for a three-dimensional net-like structure formed by conventional extrusion molding to have filaments partly tangled in loops and a two-surface or four-surface molding method of the three-dimensional net-like structure. One example is described in Patent Literature 1 in order to mold a three-dimensional net-like structure. A proposed method of molding a three-dimensional net-like structure presses down molten filaments made of or mainly made of a thermoplastic synthetic resin from a die equipped with a nozzle having a plurality of holes at an edge, makes the molten filament free fall between haul-off machines that are partly submerged in water, and hauls off the filaments at a lower speed than the falling speed, so as to manufacture a three-dimensional net-like structure. The haul-off machines are arranged to face each other to form a specified shape (for example, quadrilateral) in a direction perpendicular to the extrusion direction. The interval between the haul-off machines facing each other is set to be narrower than the width of an assembly of extruded filaments. Two surfaces or four surfaces of the outer periphery of the filament assembly are brought in contact with the haul-off machines downstream and upstream of the location where the haul-off machines are submerged in water.